using System;
using System.Collections.Generic;
using ProjectI.Builds;
using ProjectI.Enemies;
using ProjectI.Runs;
using ProjectI.Combat.Statuses;
using UnityEngine;

namespace ProjectI.Combat
{
    // Owner-local authoritative runtime. Shared assets contain no mutable field/charge state.
    public sealed class AbilityExpansionRuntime
    {
        private sealed class Field
        {
            public AbilityCastRecord Cast;public AbilityEffect Effect;public Vector3 Position;public double End,Next,Last;
            public AbilityEffectParameters Parameters;
            public float Radius,Damage,TickShield;public readonly HashSet<(ulong,uint)> Entered=new HashSet<(ulong,uint)>();
            public readonly Dictionary<(ulong,uint),float> Pulled=new Dictionary<(ulong,uint),float>();
        }
        private sealed class Pending
        {public AbilityCastRecord Cast;public Vector3 Point,Velocity;public float Damage,Radius,EdgeFraction;public double At,Last,LastVisual;public bool Stopped;public int VisualId;}
        private readonly PrototypePlayerCombat actor;
        private readonly Dictionary<int,Field> fields=new Dictionary<int,Field>(4);
        private readonly List<Pending> pending=new List<Pending>(4);
        private readonly List<int> remove=new List<int>(4);
        private readonly List<PrototypeEnemy> targets=new List<PrototypeEnemy>(64);
        private int nextProjectileVisual=1000;
        private int AllocateProjectileVisual(){if(nextProjectileVisual==int.MaxValue)nextProjectileVisual=1000;return ++nextProjectileVisual;}
        public GunTriggerWindow GunWindow {get;}=new GunTriggerWindow();
        public int FieldCount=>fields.Count;
        public int PendingCount=>pending.Count;
        public AbilityExpansionRuntime(PrototypePlayerCombat actor){this.actor=actor;}
        public static bool GroundTarget(Vector3 origin,Vector3 direction,float range,out Vector3 point)
        {
            point=default;
            if(!CombatAuthorityRules.IsValidAim(direction)||!Physics.Raycast(origin,direction,out var hit,range,~LayerMask.GetMask("Players","CombatTargets"),QueryTriggerInteraction.Ignore)||hit.normal.y<.5f)return false;
            point=hit.point+Vector3.up*.15f;return true;
        }
        public bool Preflight(AbilityTuning tuning,Vector3 origin,Vector3 direction,out Vector3 point)
        {
            point=origin;
            if(tuning==null||!CombatAuthorityRules.IsValidAim(direction))return false;
            float range=tuning.EffectParameters.PlacementMetres;
            if(range>0)return GroundTarget(origin,direction,range,out point);
            if(tuning.Effect==AbilityEffect.ShardGrenade)
            {
                if(pending.Count>=4)return false;
                point=Physics.Raycast(origin,direction,out var hit,20,~LayerMask.GetMask("Players"),QueryTriggerInteraction.Ignore)?hit.point-direction*.1f:origin+direction*20;
            }
            return true;
        }
        private float DurationBonus=>actor.StatusDurationBonus;
        private void Select(Vector3 point,float radius)
        {
            targets.Clear();foreach(var enemy in PrototypeEnemy.ActiveEnemies)
                if(enemy.IsAlive&&(enemy.AimPoint-point).sqrMagnitude<=radius*radius&&Visible(point,enemy.AimPoint))targets.Add(enemy);
            targets.Sort((a,b)=>{int distance=(a.AimPoint-point).sqrMagnitude.CompareTo((b.AimPoint-point).sqrMagnitude);return distance!=0?distance:a.TargetId.CompareTo(b.TargetId);});
        }
        private static bool Visible(Vector3 origin,Vector3 point)=>!Physics.Linecast(origin,point,~LayerMask.GetMask("Players","CombatTargets"),QueryTriggerInteraction.Ignore);
        public void Activate(AbilityActivationContext context,AbilityCastRecord cast,Vector3 prepared)
        {
            var tuning=context.Tuning;var now=cast.StartedAt;
            switch(tuning.Effect)
            {
                case AbilityEffect.GravitySnare:AddField(cast,tuning,prepared,now);break;
                case AbilityEffect.ScanPulse:
                    Select(actor.Vitals.AcceptedPosition+Vector3.up,tuning.Radius);
                    foreach(var enemy in targets)enemy.ApplyScanServer(new StatusApplication(cast.Owner,EnemyStatusId.Mark,1,tuning.Duration*(1+DurationBonus),cast.AttackId,false,tuning.Duration*(1+actor.PassiveStatusDurationBonus),cast.AbilityId),now);
                    actor.ExpansionVisualServer(cast.AbilityId,actor.Vitals.AcceptedPosition,tuning.Radius,.18f,true);break;
                case AbilityEffect.ShardGrenade:
                    var grenade=new Pending{Cast=cast,Point=cast.Origin,Velocity=cast.Direction*tuning.EffectParameters.ProjectileForwardSpeed+Vector3.up*tuning.EffectParameters.ProjectileUpwardSpeed,Damage=tuning.Magnitude,Radius=tuning.Radius,EdgeFraction=tuning.EffectParameters.EdgeDamageFraction,At=now+tuning.Duration,Last=now,VisualId=AllocateProjectileVisual()};pending.Add(grenade);
                    actor.ExpansionVisualServer(grenade.VisualId,cast.Origin,.12f,(float)tuning.Duration,false);break;
                case AbilityEffect.RepulsorBurst:
                    Select(cast.Origin,tuning.Radius);Vector3 forward=new Vector3(cast.Direction.x,0,cast.Direction.z).normalized;
                    foreach(var enemy in targets)
                    {
                        Vector3 delta=enemy.transform.position-cast.Origin;delta.y=0;
                        if(Vector3.Dot(forward,delta.normalized)<Mathf.Cos(tuning.EffectParameters.ConeHalfAngleDegrees*Mathf.Deg2Rad))continue;
                        Apply(enemy,cast,tuning.Magnitude);enemy.TryDisplaceServer(delta.normalized*tuning.EffectParameters.PushMetres,tuning.EffectParameters.PushMetres);
                    }
                    Complete(cast);actor.ExpansionVisualServer(cast.AbilityId,cast.Origin-Vector3.up*1.55f,tuning.Radius,.18f,true,false,cast.Direction,tuning.EffectParameters.ConeHalfAngleDegrees);break;
                case AbilityEffect.FocusWindow:GunWindow.Focus(now,tuning.EffectParameters.Enhancement,EffectSourceKey.Ability(tuning.Id,cast.Owner));break;
                case AbilityEffect.ArcAnchor:case AbilityEffect.WardBeacon:AddField(cast,tuning,prepared,now);break;
                case AbilityEffect.SlipstreamStep:
                    actor.ApplyDashServer(context.Direction,tuning);
                    actor.ApplyExpansionHasteServer(tuning.EffectParameters.SecondaryMovementBonus,tuning.EffectParameters.SecondaryMovementSeconds,tuning.Id);break;
                case AbilityEffect.GravityCollapse:AddField(cast,tuning,actor.Vitals.AcceptedPosition+Vector3.up*.15f,now);break;
                case AbilityEffect.RailSurge:GunWindow.Rail(now,tuning.EffectParameters.Enhancement,EffectSourceKey.Ability(tuning.Id,cast.Owner));break;
            }
        }
        private void AddField(AbilityCastRecord cast,AbilityTuning tuning,Vector3 point,double now)
        {
            fields[cast.AbilityId]=new Field{Cast=cast,Effect=tuning.Effect,Parameters=tuning.EffectParameters,Position=point,End=now+tuning.Duration,Next=now+tuning.EffectParameters.TickSeconds,Last=now,
                Radius=tuning.Radius,Damage=tuning.Magnitude,TickShield=tuning.Effect==AbilityEffect.WardBeacon?tuning.Magnitude:0};
            actor.ExpansionVisualServer(cast.AbilityId,point,tuning.Radius,(float)tuning.Duration,false,true);
        }
        public void DashWake(Vector3 point,float duration)
        {
            var cast=new AbilityCastRecord(actor,-1,point,Vector3.forward,1,false);
            fields[-1]=new Field{Cast=cast,Effect=AbilityEffect.GravitySnare,Parameters=AbilityEffectParameters.Defaults(AbilityEffect.GravitySnare),Position=point,End=cast.StartedAt+duration,Next=cast.StartedAt,Last=cast.StartedAt,Radius=2};
            actor.ExpansionVisualServer(-1,point,2,duration,false,true);
        }
        public void Echo(AbilityCastRecord cast,AbilityTuning tuning,Vector3 point,float scale)
        {
            if(!cast.Valid(actor))return;
            var echo=new AbilityCastRecord(actor,tuning.Id,cast.Origin,cast.Direction,cast.DamageMultiplier*scale,cast.IsUltimate,true,cast.AttackId);
            if(tuning.Effect==AbilityEffect.ShardGrenade)
            {if(pending.Count<8)pending.Add(new Pending{Cast=echo,Point=cast.Origin,Velocity=cast.Direction*tuning.EffectParameters.ProjectileForwardSpeed+Vector3.up*tuning.EffectParameters.ProjectileUpwardSpeed,Damage=tuning.Magnitude,Radius=tuning.Radius,EdgeFraction=tuning.EffectParameters.EdgeDamageFraction,At=echo.StartedAt+tuning.Duration,Last=echo.StartedAt,VisualId=AllocateProjectileVisual()});}
            else if(tuning.Effect==AbilityEffect.RepulsorBurst)
            {
                Select(cast.Origin,tuning.Radius);foreach(var enemy in targets)
                    if(Vector3.Dot(cast.Direction,(enemy.AimPoint-cast.Origin).normalized)>=Mathf.Cos(tuning.EffectParameters.ConeHalfAngleDegrees*Mathf.Deg2Rad))Apply(enemy,echo,tuning.Magnitude);
            }
            else if(tuning.Effect==AbilityEffect.ArcAnchor)
            {
                // One bounded secondary packet representing the authored 6s schedule; no replacement field or fresh cast credit.
                Select(point,tuning.Radius);for(int i=0;i<Math.Min(tuning.EffectParameters.MaximumTargets,targets.Count);i++)Apply(targets[i],echo,tuning.Magnitude*(float)tuning.Duration);
            }
        }
        public void Tick(double now)
        {
            for(int i=pending.Count-1;i>=0;i--)
            {
                var p=pending[i];if(!p.Cast.Valid(actor)){pending.RemoveAt(i);actor.ClearExpansionVisualServer(p.VisualId);continue;}
                double at=Math.Min(now,p.At),remaining=Math.Max(0,at-p.Last);
                while(remaining>0&&!p.Stopped)
                {
                    float step=(float)Math.Min(.05,remaining);Vector3 delta=p.Velocity*step+Vector3.down*4.905f*step*step;
                    if(Physics.SphereCast(p.Point,.1f,delta.normalized,out var hit,delta.magnitude,~LayerMask.GetMask("Players"),QueryTriggerInteraction.Ignore))
                    {p.Point=hit.point+hit.normal*.12f;p.Stopped=true;}
                    else p.Point+=delta;
                    p.Velocity+=Vector3.down*9.81f*step;remaining-=step;
                }
                p.Last=at;
                if(now>=p.At){pending.RemoveAt(i);Burst(p.Cast,p.Point,p.Radius,p.Damage,true,p.EdgeFraction);actor.ExpansionVisualServer(p.VisualId,p.Point,p.Radius,.3f,true);}
                else if(now-p.LastVisual>=.05){p.LastVisual=now;actor.ExpansionVisualServer(p.VisualId,p.Point,.12f,(float)(p.At-now),false);}
            }
            remove.Clear();
            foreach(var pair in fields)
            {
                var field=pair.Value;
                if(!field.Cast.Valid(actor)||(pair.Key==-1&&actor.UpgradeRank(UpgradeId.DashWake)==0)){remove.Add(pair.Key);continue;}
                if(now<field.Next&&now<field.End)continue;
                double at=Math.Min(now,field.End),seconds=Math.Max(0,at-field.Last);field.Last=at;field.Next=at+field.Parameters.TickSeconds;
                if(field.Effect==AbilityEffect.WardBeacon)TickWard(field,at,seconds);
                else
                {
                    Select(field.Position,field.Radius);
                    for(int i=0;i<targets.Count;i++)
                    {
                        var enemy=targets[i];var key=(enemy.TargetId,enemy.Lifetime);
                        if(field.Effect==AbilityEffect.GravitySnare)
                        {
                            if(field.Cast.AbilityId!=-1&&field.Entered.Add(key))enemy.ApplyStatusServer(new StatusApplication(field.Cast.Owner,EnemyStatusId.Snare,1,field.Parameters.RootSeconds,field.Cast.AttackId),at);
                            bool authored=field.Cast.AbilityId!=-1;
                            enemy.ApplyStatusServer(new StatusApplication(field.Cast.Owner,EnemyStatusId.Slow,field.Parameters.SlowFraction,Math.Max(.35,(field.End-at)*(1+(authored?DurationBonus:0))),field.Cast.AttackId,false,
                                Math.Max(.35,(field.End-at)*(1+(authored?actor.PassiveStatusDurationBonus:0))),field.Cast.AbilityId),at);
                        }
                        else if(field.Effect==AbilityEffect.ArcAnchor&&i<field.Parameters.MaximumTargets)Apply(enemy,field.Cast,field.Damage*(float)seconds);
                        else if(field.Effect==AbilityEffect.GravityCollapse)
                        {
                            enemy.ApplyStatusServer(new StatusApplication(field.Cast.Owner,EnemyStatusId.Slow,field.Parameters.SlowFraction,Math.Max(.35,(field.End-at)*(1+DurationBonus)),field.Cast.AttackId,true,
                                Math.Max(.35,(field.End-at)*(1+actor.PassiveStatusDurationBonus)),field.Cast.AbilityId),at);
                            field.Pulled.TryGetValue(key,out var pulled);
                            float factor=1-enemy.Resistances.DisplacementReduction;
                            float maximum=EnemyResistanceRules.ResolveDisplacement(field.Parameters.PullMetres,EnemyControlKind.Pull,enemy.Resistances);
                            float step=factor>0?Mathf.Min(Mathf.Max(0,maximum-pulled)/factor,(float)seconds*field.Parameters.PullMetresPerSecond):0;
                            Vector3 before=enemy.transform.position;
                            if(step>0&&enemy.TryDisplaceServer((field.Position-before).normalized*step,step))
                            {Vector3 travel=enemy.transform.position-before;travel.y=0;field.Pulled[key]=Mathf.Min(maximum,pulled+travel.magnitude);}
                        }
                    }
                    if(field.Effect==AbilityEffect.ArcAnchor)Complete(field.Cast);
                }
                if(now>=field.End)
                {if(field.Effect==AbilityEffect.GravityCollapse)Burst(field.Cast,field.Position,field.Radius,field.Damage,false);remove.Add(pair.Key);}
            }
            foreach(int id in remove){fields.Remove(id);actor.ClearExpansionVisualServer(id);}
        }
        private void TickWard(Field field,double at,double seconds)
        {
            // Recipient-side strongest family budget prevents four overlapping tick writers adding together.
            foreach(var ally in PrototypePlayerVitals.ActivePlayers)
            {
                if(!ally.IsSpawned||!ally.IsAlive||(ally.AcceptedPosition-field.Position).sqrMagnitude>field.Radius*field.Radius||!Visible(field.Position,ally.AcceptedPosition+Vector3.up))continue;
                ally.GrantWardFamilyServer(field.TickShield*(float)seconds,field.Parameters.TickSeconds);
            }
        }
        public bool TryGetWardBenefit(PrototypePlayerVitals recipient,double now,out PlayerBuffSnapshot benefit)
        {
            benefit=default;bool found=false;
            foreach(var field in fields.Values)
            {
                if(field.Effect!=AbilityEffect.WardBeacon||now>=field.End||!field.Cast.Valid(actor)||recipient==null||!recipient.IsAlive
                    ||(recipient.AcceptedPosition-field.Position).sqrMagnitude>field.Radius*field.Radius
                    ||!Visible(field.Position,recipient.AcceptedPosition+Vector3.up))continue;
                var candidate=new PlayerBuffSnapshot(EffectSourceKey.Ability(field.Cast.AbilityId,field.Cast.Owner),PlayerBuffEffect.WardShieldRate,field.TickShield,field.End);
                if(!found||candidate.Magnitude>benefit.Magnitude||candidate.Magnitude==benefit.Magnitude&&candidate.Source.CompareTo(benefit.Source)<0)
                {benefit=candidate;found=true;}
            }
            return found;
        }
        private void Burst(AbilityCastRecord cast,Vector3 point,float radius,float amount,bool falloff,float edgeFraction=.5f)
        {
            Select(point,radius);foreach(var target in targets)
            {float factor=falloff?Mathf.Lerp(1,edgeFraction,Mathf.Clamp01((target.AimPoint-point).magnitude/radius)):1;Apply(target,cast,amount*factor);}Complete(cast);
        }
        private void Apply(PrototypeEnemy enemy,AbilityCastRecord cast,float amount)
        {
            if(!cast.Valid(actor))return;var result=enemy.ApplyDamageServer(cast.Damage(amount,enemy.AimPoint));
            if(cast.Secondary)actor.ProcessEchoDamageResultServer(result);else actor.ProcessDamageResultServer(result);
        }
        private static void Complete(AbilityCastRecord cast)=>PrototypeRunDirector.Instance?.CompleteAttack(cast.Owner,cast.AttackId);
        public void Clear()
        {foreach(int id in fields.Keys)actor.ClearExpansionVisualServer(id);foreach(var p in pending)actor.ClearExpansionVisualServer(p.VisualId);fields.Clear();pending.Clear();GunWindow.Clear();}
        public void RemoveField(int id){if(fields.Remove(id))actor.ClearExpansionVisualServer(id);}
    }
}